1. Field of the Invention
The present invention relates to a semiconductor device having contact etching stopper films with different stresses and a method of manufacturing the same.
2. Description of the Related Art
In the prior art, when a dual stopper film (dual liner film) is introduced, a gap is formed between the stopper film of an nMOSFET and that of a pMOSFET due to misalignment or dimensional variations in lithography for stopper film patterning. As a result, the substantial function of the stopper film which should serve as an etching stopper at the time of contact formation is lost. To prevent this, a stopper film overlap region must be provided at the boundary between the nMOSFET and the pMOSFET. In the process of forming holes in stopper films by contact etching, the necessary etching amount of the stopper film on the gate electrode is about twice that on the element region. To form contacts in both films, overetching is performed to form contacts in the stopper film on the element region. Since a silicide film or shallow trench isolation (STI) structure is largely etched, junction leakage may occur.
Prior art reference information about the present invention is as follows.
[Patent Reference 1] Jpn. Pat. Appln. KOKAI Publication No. 2002-198368